LIB. II. 36. 245 



crucis. Sumatur horologium 14 ex iis, quoa moventur 

 per pondera plumbea ; et aliud ex iis, quae moventur 

 per compressionem laminae ferreae ; atque vere proben- 

 tur, ne alterum altero velocius sit, atit tardius ; deincle 

 ponatur horologium illud movens per pondera super 

 fastigiura alicujus templi altissimi, altero illo infra de- 

 tento ; et notetur diligenter, si horologium in alto 

 situm tardius moveatur quam solebat, propter climi- 

 nutam virtutem ponderum. Idem fiat experimentum 

 in profundis minerarum alte sub terra depressarum ; 

 utrum horologium hujusmodi non moveatur velocius 

 quam solebat, propter auctarn virtutem ponderum. 

 Quod si inveniatur virtus ponderum minui in sublirni, 

 aggravari in subterraneis ; recipiatur pro causa ponderis 

 attractio a massa corporea terrac. 



(4.) Similiter, sit natura inquisita, verticitas acus fer 

 reae, tactae magnete 15 . Circa hanc naturam tale erit 

 bivium. Necesse est, ut tactus magnetis vel ex se 

 indat ferro verticitatem ad septentriones et austrum ; 

 vel ut excitet ferrum tantummodo et habilitet : motus 

 auteni ipse indatur ex pracsentia terrac, ut Gilbertus 

 opinatur, et tanto conatu probare nititur. Itaque hue 

 spectant ea, qua? ille perspicaci industria conquisivit. 

 Nimirum quod clavus ferreus, qui diu duravit in situ 

 versus septentriones et austrum, colligat mora diutina 

 verticitatem, absque tactu magnetis : ac si terra ipsa, 

 qua3 ob distantiam debiliter operatur, (namque super- 



14 This example will not do. The which before attracted downwards, 



&quot; Horologium,&quot; or fly-clock, would and now upwards, 

 act well enough were the earth sta- 15 The Polarity of the Needle, 



tionary, and were there no other This section is ingenious. We here 



active force. Besides, the gravity meet Gilbert again. It was with 



at the bottom of a mine would be such a &quot; terrella,&quot; or little globe, as 



less : both because of the actual Bacon here proposes to use, that 



diminution, and of the mass of Gilbert made his experiments. See 



matter now placed above the point, supr. I. 54. 



